Z's a tough nut to crack. Nevermind the fact that he spent his first few years on Copper 9 as an emotionless killing machine who only ever frowned. That's a different story. This is about the phase after that one.
Z first showed signs of proper emotion when he decided not to kill a Worker Drone while out on a hunt (a decision that pissed off X to NO END). Within two weeks, an inhibitor in his programming was corrupted for mysterious reasons (*cough cough*haventwrittenanyyet*cough cough*), and his eyes and acid became red. Next thing he knew, he was flying through the ruins while his former teammates chased him around.
After his daring/narrow/overhyped escape from his former teammates, he hid in a cave. This cave just so happened to be home to a defective Disassembly Drone known only as 26. He and 26 became fast friends, and soon found themselves helping each other out.
Then, Z's life changed again.
While out on a scavenging mission, Z and 26 crossed paths with X and Y. A clash ensued. And who was standing off to the side? None other than Emily. I've already told you how that went, but I didn't tell you the rest of her story.
Emily and Z loved together in the cave for several weeks, waiting for 26. When he didn't return after the seventh one, Z knew something was up. So, he and Emily went looking for him. I'll tell you that part later. To sum up: Z kicked X's ass, screwed Y over in five different flavors of "dead" (but she came back, she always comes back, like William Afton if he was a murderous genocide robot), and Emily decided she and Z were dating. Hope you enjoyed this one. See you next time.